(a) Field of the Invention
The present invention relates to a system and method of cell balancing, and more particularly, to a system and method for cell balancing of a battery pack.
(b) Description of the Related Art
Vehicles equipped with an internal combustion engine that uses gasoline or heavy oil as the main fuel have an influence on air pollution and generation of pollutants. Accordingly, many efforts have been made in recent years to develop electric vehicles or hybrid vehicles to reduce generation of pollutants.
An electric vehicle is a vehicle that uses a battery engine operated by electric energy output from a battery. Since electric vehicle use a battery formed by assembling a plurality of chargeable and dischargeable secondary cells in one pack as the main power source, exhaust gas production and noise is reduced. A hybrid vehicle is a vehicle that uses two or more power sources, for example, an internal combustion engine and a battery engine. Currently, complex types of hybrid vehicles that use an internal combustion engine and a fuel cell that generates electric energy by making a chemical reaction while continuously supplying hydrogen and oxygen, or using a battery and a fuel cell have been developed.
Furthermore, vehicles that use a battery engine, as described above, increase in the number of secondary cells to improve the power source and as battery management system (BMS) and require a control method of cell balancing to efficiently manage a plurality of connected cells and packs. In common vehicles, when a relay is connected to a battery pack in electric vehicles to supply power large power, the voltage deviation between battery packs may be naturally balanced. However, the inter-cell voltage deviation in the battery pack may not be reduced, and when the battery is charged/discharged with an inter-cell voltage deviation in the battery pack, the voltage deviation between the cells in the battery pack increases.
The above information disclosed in this section is merely for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.